/**
 *       Copyright (c) 2012 Lukas Zaruba
 *
 *   This file is part of Robot Playground.
 *
 *   Robot Playground is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   Robot Playground is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with Robot Playground. If not, see <http://www.gnu.org/licenses/>.
 */
package net.zarubsys.commons.scripting.functions.strings;

import java.util.Iterator;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import net.zarubsys.commons.scripting.IScriptFunction;
import net.zarubsys.commons.scripting.ParsedStatement;
import net.zarubsys.commons.scripting.ScriptingEnvironment;
import net.zarubsys.commons.scripting.ScriptingException;
import net.zarubsys.commons.utils.StringUtils;

/**
 * Based on scripting language from Media Solutions Slovakia, a.s.
 * @author Lukas Zaruba, lukas.zaruba@gmail.com
 */
public class MatchedGroupFunction implements IScriptFunction {

    public String getName() {
        return "matchedGroup";
    }

    public int getMinArgsNum() {
        return 2;
    }

    public int getMaxArgsNum() {
        return 3;
    }

    public Object execute(ScriptingEnvironment env, List<ParsedStatement> args) throws ScriptingException {
        Iterator<ParsedStatement> iter = args.iterator();
        String text = StringUtils.toString(iter.next().execute(env));
        String regex = StringUtils.toString(iter.next().execute(env));
        int groupNum = 1;
        if (iter.hasNext()) { 
            groupNum = Integer.parseInt(StringUtils.toString(iter.next().execute(env)));
        }

        Matcher matcher =  Pattern.compile(regex).matcher(text);
        String result = null;
        if(matcher.matches()) {
            result = matcher.group(groupNum); 
        }
        return result != null ? result : "";
    }

}
